PFX certificate

We have a Pro plan and the developers are now asking for a PFX certificate. Can someone help me pls?
The website is showing a certificate issued by COMODO ECC issued by ssl391400.cloudflaressl.com.

Thanks

PFX is a certificate format. What exactly do they want? The certificate on Cloudflare is not exportable. Well, the certificate - being public - of course is, but they private part is not. Were they referring to the certificate on your server?